Messages in this thread |  | | Date | Fri, 25 Oct 2013 06:34:54 -0700 | From | Kees Cook <> | Subject | RW and executable hole in page tables on x86_64 |
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Hi,
I've noticed there's a chunk of kernel memory still marked RW and x. See 0xffffffff82956000 below...
---[ High Kernel Mapping ]--- 0xffffffff80000000-0xffffffff81000000 16M pmd 0xffffffff81000000-0xffffffff81a00000 10M ro PSE GLB x pmd 0xffffffff81a00000-0xffffffff81e00000 4M ro PSE GLB NX pmd 0xffffffff81e00000-0xffffffff82200000 4M RW GLB NX pte 0xffffffff82200000-0xffffffff82800000 6M RW PSE GLB NX pmd 0xffffffff82800000-0xffffffff82956000 1368K RW GLB NX pte 0xffffffff82956000-0xffffffff82a00000 680K RW GLB x pte 0xffffffff82a00000-0xffffffffa0000000 470M pmd
HPA looked at it for a bit, but it wasn't obvious what was going on. It's after the end of bss. I do note that the two adjacent regions add up to 2MiB. Is this some kind of leftover mapping? What is this region? Is there a sensible place to clean it up?
Thanks,
-Kees
-- Kees Cook @outflux.net
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